Chemical abundances in the metal-intermediate GC NGC 6723

Abstract

We have performed a detailed spectral analysis of the inner halo Galactic globular cluster (GC) NGC 6723 using high resolution (R$\approx$ 22000-48000) spectra for for eleven red giant branch stars collected with MIKE (Magellan) and FEROS (MPG/ESO). This globular is located at the minimum of the bimodal metallicity distribution of GCs suggesting that it might be an excellent transitional system between metal-intermediate and metal-rich GCs. In spite of its metal-intermediate status, it is characterized by an extended horizontal branch and by a large number of RR Lyrae stars. We investigated abundances of a variety of species including light, $\alpha$-, Fe-peak, and neutron capture elements. We found a mean metallicity $[Fe/H]=-0.93\pm 0.05$ dex, and a typical $\alpha$ -enrichment ($[\alpha /Fe]\approx 0.39$) that follows the trend of metal-poor and metal-intermediate GCs. The same outcome applies for light metals (Na, Al), Fe-peak (V, Cr, Mn, Fe, Co, Ni, Cu), $s$/$r$-process elements (Ba, Eu) and for the classical anti-correlation: Na-O and Mg-Al. The current findings further support the evidence that the chemical enrichment of NGC 6723 is in more line with metal-intermediate GCs and their lower metallicity counterparts, and it does not bring forward the prodrome of the metal-rich regime.

MNRAS, accepted for publication

References in corpus (16)

• The Gaia mission
• The Dartmouth Stellar Evolution Database
• Galactic chemical evolution: Carbon through Zinc
• The Dawes Review 2: Nucleosynthesis and stellar yields of low and intermediate-mass single stars
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. IX. The Atlas of Multiple Stellar Populations
• A new implementation of the infrared flux method using the 2MASS catalogue
• NLTE abundances of Mn in a sample of metal-poor stars
• Chemical similarities between Galactic bulge and local thick disk red giant stars
• Light, Alpha, and Fe-Peak Element Abundances in the Galactic Bulge
• High-resolution abundance analysis of red giants in the globular cluster NGC 6522
• The Chemical Composition of the Galactic Bulge and Implications for its Evolution
• VLT-UVES abundance analysis of four giants in NGC 6553
• 3D Stellar Reddening Map from 2MASS Photometry: An Improved Version
• The Na-O anticorrelation in horizontal branch stars. V. NGC 6723
• Light-Element Abundances of Giant Stars in the Globular Cluster M71 (NGC 6838)
• Reversed radial distribution trend of subpopulations in the globular clusters NGC 362 and NGC 6723

Cited by in corpus (6)

• Evidence for a bottom-light initial mass function in massive star clusters
• APOGEE discovery of a chemically atypical star disrupted from NGC 6723 and captured by the Milky Way bulge
• Excess of Ca (and Sc) produced in globular cluster multiple populations: a first census in 77 Galactic globular clusters
• Isochrone fitting of Galactic globular clusters -- IV. NGC6362 and NGC6723
• The in situ origin of the globular cluster NGC 6388 from abundances of Sc, V, and Zn of a large sample of stars
• Integrated Spectra of Milky Way Globular Cluster